Method of making a switching assembly



Dec. 14, 1965 R H, MARKS 3,222,758

METHOD OF MAKING A SWITCHING ASSEMBLY Filed Jan. 3l, 1962 BY mmmmwlmmwm www I Arran/5v5 United States Patent 3,222,758 METHOD 0F MAKING A SWITCHING ASSEMBLY Richard H. Marks, Chicago, Ill., assignor to C. P. Clare & Company, Chicago, lll., a corporation of Delaware Filed Jan. 31, 1962, Ser. No. 170,122 8 Claims. (Cl. 29-155.5)

This invention relates to a switching assembly and, more particularly, to a new and improved switching assembly using sealed switch units.

With the increased use of individual sealed switch units or capsules to perform switching functions previously performed by conventional telephone type relays, it is often desirable to have arrangements or assemblies including a plurality of individual sealed switch capsules that provide the same contact types or switching functions as telephone relays. One common type of switching arrangement is a nonbridging trasfer or form C cotact assembly in which a pair of normally closed contacts are opened before a pair of normally open contacts are closed when the relay is operated Another arrangement is a bridging (make-before-break) or form D contact assembly in which the operation of the relay closes the normally open contacts prior to the opening of the normally closed contacts. In certain relays, the contacts are selectively operated in dependence upon the polarity of the input voltage or signal.

In the past, form C contact assemblies using sealed switch capsules have been provided by using an unbiased switch unit paired with a switch capsule having a bias magnet that normally holds the biased switch unit in an operated condition. When a magnetic field of the proper polarity is applied,the unbiased switch capsule is operated and the bias capsule is released. However, this arrangement cannot be used to provide either form C or form D contacts and is not capable of providing either a chopper driven by a sinusoidal input voltage or a bistable or latching relay capable of operating on relatively short input pulses.

Accordingly, one object of the present invention is to provide a new and improved switching assembly.

Another object is to provide a switching assembly providing either bridging or nonbridging transfer contacts.

Another object is to provide a switching assembly that can be used as a chopper driven by a sinusoidal input voltage or a bistable or latching relay capable of operating on short duration input pulses.

A further object is to provide a switching assembly including a pair of sealed switch units that are provided with common operating means and individual and oppositely poled biasing means to provide either form D contacts or form C contacts.

Another object is to provide a switching assembly including a pair of sealed switch units that are provided with relatively heavy and oppositely directed biases to provide form D contacts or with relative light and oppositely directed biases to provide form C contacts.

Another object is to provide a method of making switching assemblies having either bridging or nonbridging contacts.

In accordance with these and many other objects, an embodiment of the invention comprises a common winding means having an axially extending opening in which are disposed a pair of sealed switch units or capsules. Each of the sealed switch units includes a pair of magnetic elements which are moved into engagement in response to the application of a magentic field of a first value or strength and which are held in engaged position until the applied magnetic field drops to a second or release value or strength less than the first strength. Each of the sealed switch units is provided with an individual bias magnet, and the bias fields for the two switch units are oppositely directed. The strength of the bias field provided by each of the bias magnets is in the range between the first and second values, and one of the sealed switch units is operated in the normal condition of the switching assembly.

When the switching assembly is to provide form C or nonbridging transfer contacts, the strength of the bias magnets is adjusted so as to fall closer to the first strength than the second strength. When an input signal of a proper polarity is applied to the common winding means so as to oppose the field produced by the bias magnet associated with the normally operated switch unit, the effective field acting on the engaged magnetic elements is first reduced to a strength below the second strength so that these contacts open. A subsequent increase in the flux field produced by the energization of the 0perating winding then closes the normally open contacts so that the normally open contacts are closed following the opening of the normally closed contacts to provide form C contacts.

When the switching assembly is to provide bridging or form D contacts, the strength of the field provided by the bias magnets is increased in the range between the first and second strengths to be closer to the second strength. When the winding means is energized with a signal of a polarity to oppose the lield of the bias magnet associated with the normally closed magnetic contacts, the effective field acting on the normally open contacts first reaches the first strength so that the normally open contacts are closed and, thereafter, the bias field applied to the normally closed contacts is overcome to open these contacts. Thus, the normally open contacts are `first closed followed by the opening of the normally closed contacts to provide form D contacts. Since both of the bias magnets provide fields exceeding the second strength in both form C and form D contact assemblies, the switching assembly remains in the condition to which it was operated when the energizing signal is removed. An oppositely poled input signal returns the switching assembly to its original condition.

Many other objects and advantages of the present invention will become apparent from considering the following detailed description in conjunction with the draw` ings, in which:

FIG. 1 is a perspective view of a switching assembly embodying the present invention;

FIG. 2 is an enlarged sectional view taken along line 2-2 in FIG. 1;

FIG. 3 is a sectional view taken along line 3-3 in FIG. 2; and

FIG. 4 is a sectional View taken along line 4 4 in FIG. 2.

Referring now more specifically to the drawings, therein is illustrated a switching assembly, indicated generally as 10, which embodies the present invention and which includes a winding means 12 defining an axially extending opening 14 in which are disposed two sealed switch units 16 and 18. A pair of permanent magnets 20 and 22 are individually disposed adjacent the sealed switch units 16 and 1S and provide oppositely directed biasing fields for the magnetic elements in the switch units 16 and 18. By adjusting the magnitude or strength of the fields provided by the biasing magnets 20 and 22, the sealed switch capsules 16 and 18 can be made to provide form C or form D switching functions when the common winding means 12 is energized. These magnets make the switching assembly 10 bistable so as to provide a latching relay capable of operating on short pulses and also render the switching assembly capable of providing a chopper driven by a sinusoidal input signal.

The winding means 12 includes a coil bobbin 24 which defines the axially extending opening 14 and on which a winding 26 is disposed. The outer surface of the winding 26 is covered by a dielectric layer 28 (FIGS. 3 and 4). A pair of magnetic plates 30 are disposed on opposite sides of the winding 26 along the flat sides thereof to provide a magnetic return path for the flux or magneti-c field generated by the energization of the coil or winding 26. The magnetic plates 30 are held in place by an outer layer of dielectric material 32.

The sealed switch units 16 and 18, which are disposed in the axial opening 14, can be of any of the well known constructions, such as a dry type switch or a mercury wetted switch. The switch units 16 and 18 illustrated in the drawings are identical and are of the dry type in including an elongated dielectric or glass envelope 34 in which are disposed a pair of magnetic elements 36 and 38. The inner ends 36a and 38a of the magnetic elements 36 and 38 overlap and are normally maintained in a spaced relation to dene a gap. When a magnetic field of a first strength or value is applied to the magnetic elements 36 and 38, the overlapping portions 36a and 38a move into engagement to complete an electric circuit through the switch unit 16 or 18. The switch units 16 and 18 also have the characteristic that once the magnetic elements 36 and 38 have been moved into engagement, they can be retained in this condition by the application of a magnetic or flux field of a second value or strength substantially less than that of the field required to move these elements into engagement.

In one switching assembly manufactured in accordance with the present invention, the magnetic elements 36 and 38 are moved into engagement by a magnetic field having a strength of 100i15 ampere-turns and released when the applied magnetic field is reduced to a strength of 30x 10 ampere-turns. The switch units 16 and 18 can be provided with bent or offset end portions 36b and 38b on the magnetic elements 36 and 38. These bent portions can provide means for electrically connecting the switch units 16 and 18 to a printed circiut pattern and means for physically mounting the switching assembly 10 on the printed circuit panel.

The permanent magnets 20 and 22 provide means for biasing the sealed switch units 16 and 18 with magnetic fields having strengths falling between the first value at which these switches are operated and the second or lower value at which the switches are released. This bias renders the switching assembly 10 capable of remaining in the condition to which it was operated by a prior input signal, i.e., bistable, and provides means by which the adjustment of the strengths of the fields of the magnets 20 and 22 within the range controls the switching units 16 and 18 to provide either bridging or nonbridging assemblies. The permanent magnets 20 and 22 are secured to the housings or envelopes 34 of the switch units 16 and 18 in proximity to the gaps defined by the overlapping ends 36a and 38a of the magnetic elements 36 and 38 by a quantity of epoxy resin cement 40. The switch capsules 16 and 18 are disposed within the axial opening 14 with the permanent magnets 20 and 22 spaced from each other so as to reduce magnetic interaction between the permanent magnet 20 and the switch unit 18 and between the permanent magnet 22 and the switch unit 16. These magnets are also disposed so as to lie substantially within a plane passing through the gaps defined by the overlapping portions 36a and 38a of the magnetic elements 36 and 38 (FIG. 4).

In one method of making the switching assembly 10, the permanent magnets 20 and 22 are first mounted on the dielectric envelopes 34 of the switch units 16 and 18, and a single one of these switch units is placed in a test fixture =in which the connected permanent magnet 20 or 22 is saturated. A winding forming a portion of the test fixture is then energized to reduce the strength of the field provided by the bias magnet 20 or 22 to the point at which the desired operating characteristics are obtained. lf the sealed switches 16 and 18 are to be used in an arrangement providing form C contacts, the strength of the permanent magnet 20 or 22 is reduced to a point at which it provides a bias of a strength closer to the second value, for instance 45 ampere-turns. Alternatively, if the switch units 16 and 18 are to be used in an arrangement providing for D contacts, the strength of the bias field provided by the magnet 20 or 22 is reduced to a value closer to the first value, for instance 75 ampere-turns. A pair of switches 16 and 18 having substantially identical operating characteristics are then assembled with the winding means 12.

Another method of forming the switching assembly 10 is to insert a pair of switches 16 and 18 within the axial opening 14 in the winding means 12 with the permanent magnets 20 and 22 secured in position thereon. The magnets 20 and 22, which are saturated prior to insertion into the winding means 12, are then simultaneously demagnetized to reduce their field to a value between the operate (first) and release (second) values and located closer to either the operate or release values in dependence on whether form D or form C contacts are desired.

In the normal condition of the switching assembly 10, one of the switch units 16 or 18 is in an operated condition in which the magnetic elements 36 and 38 are in engagement, and the other of the switch units` 16 or 18 is in a normal condition in which a gap is provided between the overlapping ends 36a and 38a of the magnetic elements 36 and 3S. In FIG. 4 of the drawings, the switch unit 16 is shown in a normal or open condition, and the switch unit 18 is shown in an operated or closed condition. Assuming that the assembly 1@ provides form C contacts with the permanent magnets, 20 and 22 providing fields of strengths around 45 ampere-turns, the winding 26 is energized with an input signal of a polarity such that the induced flux field opposes the field provided by the bias magnet 22 on the normally closed switch unit 18 and aids the field of the magnet 20 associated with the normally open switch unit 16. When the field due to the energized winding 26 has increased to a value around l5 ampere-turns, the effective field applied to the magnetic elements 36 and 38 in the switch unit 16 is only 60 ampere-turns, and these contacts do not close.

However, the l5 ampere-turn field provided by the energized winding 26 opposes the 45 ampere-turn bias provided by the magnet 22 and reduces the effective field applied to the magnetic elements 36 and 38 in the normally closed switch unit 18 to around 30 ampere-turns. In this. range, the inherent resilience of the magnetic elements 36 and 38 in the switch unit 18 is effective to separate these elements so that the normally closed contacts provided by this switch unit are opened. As the magnetic field produced by the energization of the winding 26 increases, the effective field acting on the elements 36 and 38 in the switch unit 16 produced by the addition of the induced field from the energized winding 26 and the bias eld provided by the permanent magnet 28 reaches the range of ampere-turns. At this time, the magnetic elements 36 and 38 in the normal switch unit 16 are moved into engagement to complete a conductive circuit therethrough. Accordingly, the switching assembly 18 provides form C contacts in which the normally closed contacts in the switch unit 18 are opened prior to the closure of the contacts provided by the switch unit 16.

The switching assembly 10 remains in this condition with the contacts in the unit 16 closed and the contacts in the unit 18 open when the energizing signal is removed from the winding 26 because the 45 ampere-turn bias provided by the magnets 20 and 22 exceeds the release range of around 30 ampere-turns. When a signal of reversed polarity is applied to the winding 26, the contacts 16 are opened prior to the closure of the contacts 18 in the manner described above.

Assuming that the permanent magnets 20 and 22 provide a bias of around 75 ampere-turns, the switching assembly provides form D contacts. The energization of the winding 26 with an input signal of a polarity producing a field opposing that of the bias magnet 22 associated with the normally operated switch 18 provides a eld aiding the bias field from the magnet 20. When the induced field reaches a value of approximately 25 ampereturns., the effective field applied to the elements 36 and 38 in the normally open switch unit 16 is around 100 ampereturns, and the magnetic elements 36 and 38 in this switch funit move into engagement to complete a conductive circuit therethrough. As the induced field due to the energization of the winding 26 increases to approximately 45 ampere-turns, the effective field applied to the magneti-c elements 36 and 38 in the operated switch unit 18 is reduced to around 30 ampere-turns, and the inherent resilience of these elements moves them out of engagement so that the contacts in the switch unit 18 are opened. Thus, the energization of the winding 26 first closes the contacts in the open -switch unit 16 and then opens the normally closed contacts in the switch unit 18 to provide form D contacts. The switching assembly 10, when providing form D contacts, is also bistable inasmuch as the bias of 75 ampere-turns provided by the magnets 20 and 22 exceeds the release value of 30 ampere-turns. Accordingly, when the energizing signal is removed from the winding 26, the contacts in the switch unit 16 remain closed and the contacts in the switch unit 18 remain in an opened condition. The switch =units 16 and 18 are restored to their alternate condition by the application of an energizing signa-l of reversed polarity to the winding 26.

Although the present invention has been described with reference to a single illustrative embodiment thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this invention.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. A method of making switching assemblies using sealed switch units that are operated by the application of a field of a first strength and lare released when the applied field drops to a second strength less than said first strength, which method comprises the steps of disposing magnetically saturated permanent magnets of opposite polarities adjacent a pair of the sealed switch units, and adjusting the strengths of the fields of said permanent magnets to fall in the range between said first land second strengths and closer to said first strength than said second strength.

2. A method of making switching assemblies using sealed switch units that are operated by the application of a field of a first strength and are released when the applied field drops to a second strength less than said first strength, which method comprises the steps of disposing magnetically saturated permanent magnets of opposite polarities adjacent a pair of the sealed switch units, and adjusting the strengths of the fields of said permanent magnets to fall within the range between said first and seconds strengths and closer to said second strength than said first strength.

3. A method of making switching assemblies using a pair of sealed magnetic switches that operate in a first mode to provide transfer contacts and in a second mode to provide make-before-break contacts, the sealed magnetic switches having the characteristic of' being operated by the application of a field of a first strength and being released when an applied field falls below a second strength, which method comprises applying permanent magnetic bias fields of opposite polarities to the .pair of sealed magnetic switches, and selectively adjusting the strengths of both bias fields to have a value falling between the first and second strengths and closer to the second strength than the first strength when the switching assembly is to operate in the first mode and to have a value falling between the first and second strengths and closer to the first strength than the second strength when the switching assembly is to operate in the second mode.

` 4. A method of making switching assemblies using a pair of sealed magnetic switches that operate in a first mode to provide transfer contacts and in a second mode to provide make-before-break contacts, the sealed mag netic switches having the characteristic of being operated by the application of a field of a first strength and being released when an applied field falls below a second strength, which method comprises disposing a pair of permanent magnetic means adjacent the pair of sealed magnetic switches to apply magnetic bias fields of opposite polarities to the pair of switches, magnetically saturating the permanent magnetic means, and selectively reducing the strengths of both bias fields to have a value falling between the first and second strengths and closer to the second strength than the first strength when the switching assembly is to operate in the first mode and to have a value falling between the first and second strengths and closer to the first strength than the second strength when the switching assembly is to operate in the second mode.

5. A method of adjusting switching assemblies containing at least two sealed magnetic switches each biased by one of a pair of oppositely poled permanent magnetic means to operate in a first mode providing transfer contacts and in a second mode providing make-before-break contacts, the sealed magnetic switches having the characteristic of being operated by the application of a field of a first strength and being released when an applied field falls below a second strength, which method comprises magnetically saturating the permanent magnetic means, and selectively adjusting the strengths of the bias fields applied to the sealed magnetic switches by the permanent magnetic means to have a value falling between the first and second strengths and closer to the second strength than the first strength when the switching assembly is to operate in the first mode and to have a value falling between the first and second strengths and closer to the first strength than the second strength when the switching assembly is to operate in the second mode.

6. A method of making switching assemblies using a pair of sealed magnetic lswitches that operate in a first mode to provide transfer contacts and in a second mode to provide make-before-break contacts, the sealed magnetic switches having the characteristic of being operated by the application of a field of a first strength and being released when an applied field falls below a second strength, which method comprises applying permanent magnetic bias fields of opposite polarities to the pair of sealed magnetic switches, and selectively adjusting the strength of the bias field applied to each switch to have a value falling between the first and second strengths and closer to the `second strength than the first strength when the switch is to operate in the first mode and to have a value falling between the first and second strengths and closer to the first strength than the second strength when the switch is to operate in the second mode.

7. A method of adjusting switching assemblies using a pair of sealed magnetic switches that operate in a first mode to provide transfer contacts and in a second Inode to provide make-before-break contacts, the sealed magnetic switches having the characteristic of being operated by the application of a field having a strength on the order of ampere-turns and being released when the strength of the applied field falls below a Value on the order of 30 ampere-turns, which method comprises applying permanent magnetic bias fields of opposite polarities to the pair of sealed magnetic switches, and selectively adjusting i the strengths of both bias elds to have a value on the order of 45 ampere-turns when the switching assembly is to operate in the rst mode and to have a value on the order of 75 ampere-turns when the switching assembly is to operate in the second mode.

8. A method of adjusting switching assemblies using a pair of sealed magnetic switches to operate in a rst mode providing transfer contacts and in a second mode providing make-before-break contacts, the sealed magnetic switches having the characteristic of being operated by the application of a eld having a strength on the order of NI and being released when the applied eld falls below a strength on the order of NI/ 3, which method comprises applying permanent magnetic bias elds of opposite polarities to the pair of sealed magnetic switches, and selectively adjusting the strengths of both bias elds to a value on the order of NI/ 2 to NI/ 2.5 when the switching assembly is to operate in the rst mode and to have a 8 value on the order of NI/ 1.2 to NI/ 1.5 when the switching assembly is to operate in the second mode.

References Cited by the Examiner UNITED STATES PATENTS 2,877,315 3/1959 Oliver 20G-93.4 2,877,316 3/1959. Peek 20G-93.4 2,902,558 9/1959 Peek 20D-93.4 2,925,646 2/1960 Walsh 29-155.55 2,978,556 4/1961 Lohs et al 20G-93.4 3,015,707 1/ 1962 Perreault 20G- 93.4 3,020,369 2/1962 Jacobson 20G-104.1 3,020,626 2/1962 Dowdle 29-155.55 3,061,696 10/1962 Peek.

WHITMORE A. WILTZ, Primary Examiner.

BERNARD A. GILHEANY, JOHN F. CAMPBELL,

Examiners. 

1. A METHOD OF MAKING SWITCHING ASSEMBLIES USING SEALED SWITCH UNITS THAT ARE OPERATED BY THE APPLICATION OF A FIELD OF A FIRST STRENGTH AND ARE RELEASED WHEN THE APPLIED FIELD DROPS TO A SECOND STRENGTH LESS THAN SAID FIRST STRENGTH, WHICH METHOD COMPRISES THE STEPS OF DISPOSING MAGNETICALLY SATURATED PERMANENT MAGNETS OF OPPOSITE POLARITIES ADJACENT A PAIR OF THE SEALED SWITCH UNITS, AND ADJUSTING THE STRENGTHS OF THE FIELDS OF SAID PERMANENT MAGNETS TO FALL IN TNE RANGE BETWEEN SAID FIRST AND SECOND STRENGTHS AND CLOSER TO SAID FIRST STRENGTH THAN SAID SECOND STRENGTH. 